During the preparation of transmission electron microscopy (TEM) samples, a mask or template is placed over a sample or specimen to allow a selective area to be eroded through acid etching. One common factor when preparing samples that require the use of highly corrosive etchants has been to use wax to mask the area not to be etched. One such process is the jet etch process where the sample is masked and mounted with wax.
Another procedure is to manually prepare samples which are entirely covered with wax except for the portion to be etched. Because manually prepared samples need little hardware set-up, the costs of the operation are mostly personnel related costs, therefore process steps that can be removed result in money saved. The drawback is the difficulty of monitoring the etch erosion.
In either case, once the etching is complete, the wax or stop-off must be removed with an adequate solvent. For the manual preparation of a common 100 micron thick sample, this process can be rather labor intensive and create chemical waste from both the etchant as well as the solvent used for the mask removal. In the jet etch process, the wax removal cannot be automated because the sample is also mounted using the wax. This necessitates the manual handling of the sample specifically for post etch cleaning.